Number 355 (Story #1), January 20, 1998 by Phillip F. Schewe and Ben Stein|
THE UNIVERSE WILL EXPAND FOREVER. This prediction is based on new studies of distant supernovas. Because Type Ia supernovas (supernovas in which material falling onto a white dwarf from a companion object ignites violently) brighten and fade in such a predictable way, their intrinsic brightness (and their distances from Earth) can be determined by carefully watching light emission over time. Combining these distances with the velocities of the host galaxies (determined from redshifts) allows one to calculate the expansion of the universe with some confidence. And the result appears to suggest that the universe does not have enough matter (visible or dark) to halt the current expansion. This view emerged two weeks ago at the meeting of the American Astronomical Society in Washington, where optical data for many new supernovas (including the most distant supernova ever observed, one with a redshift of 0.97) were reported by a group from LBL (led by Saul Perlmutter) and one from Harvard-Smithsonian (Peter Garnavich). The new findings are consistent with an age estimate for the universe of 15 billion years.